Acrylic sheets, polycarbonate articles, and other plastic transparent articles have satisfactory lightweightness, transparency, workability, resistance to breaking, and safety upon breaking and are thereby used particularly in personal protective equipment such as sport goggles, helmet shields, safety goggles, and safety shields; industrial uses such as covers for display equipment and measuring instruments, lenses, and sensor covers; household appliances such as partitions and display cases in houses and stores; and uses associated with transportation, such as partitions, shelves, measuring instrument covers, and windows for automobiles and railway vehicles. Plastic materials for these uses, when used under conditions of high ambient temperature and humidity or under conditions with a large difference in temperature and/or in humidity, may fog and lose transparency due to dewing on the surface. To solve these disadvantages, a technique has been employed. This technique includes coating a substrate surface with an anti-fog composition including a nonreactive surfactant. Anti-fog properties obtained by this technique, however, decrease upon wiping out of the treated surface and lack durability, although the anti-fog properties are effectively exhibited in early stages after the coating. To improve durability of anti-fog properties, a technique has been proposed, which technique includes applying a hydrophillic polymer such as a poly(hydroxyalkyl(meth)acrylate) to an article, and thermally curing the applied polymer to form a film to thereby impart anti-fog properties to the article. The resulting article obtained by this technique, however, fails to have sufficient anti-fog performance although exhibiting certain anti-fog properties for a longer duration. In addition, the article disadvantageously has practically insufficient mechanical strengths (e.g., scratch resistance) or, when thermally formed typically into a goggle, has reduced anti-fog properties due to heat upon forming.
Patent Literature (PTL) 1 proposes, for better scratch resistance, an anti-fog coating composition which includes a polymer including an acrylamide compound as a copolymerized component, an epoxy-containing polymer, an epoxy-containing silane coupling agent, and a compound having a melamine skeleton in combination and which is thermally curable. However, it takes about one hour to cure the resin composition at 130° C. In addition, the resin composition as a mixture can be stored stably only in a short time and disadvantageously causes extremely inferior productivity.
PTL 2 proposes an active-energy-ray-curable anti-fog composition including a di(meth)acrylate having an alkylene glycol skeleton in combination with a reactive surfactant having an unsaturated group. The composition, however, has extremely low curability as compared to those of regular active-energy-ray-curable resins and disadvantageously has insufficient practical productivity, although the resulting cured article exhibits anti-fog performance for a longer duration. PTL 3 proposes a urethane(meth)acrylate having an alkylene glycol skeleton. The urethane(meth)acrylate, however, disadvantageously exhibits anti-fog performance lasting for an extremely short time in environments assumed in household appliance uses or vehicle uses, because the alkylene glycol skeleton is liable to be oxidized in a hot and humid environment. In contrast, PTL 4 proposes the use of a compound having an alkylene glycol skeleton in combination with an oxidation inhibitor (e.g., an ultraviolet absorber or thermal stabilizer) for helping the compound to have better durability in a hot and humid environment. The resulting article, however, disadvantageously gradually deteriorates in appearance because the oxidation inhibitor is oxidized by itself and colored.